Knit pile carpet fabric

ABSTRACT

A warp knit pile fabric and method of making the same wherein a base fabric is formed from spaced rows of warpwise extending chain stitches interconnected by laid in weft yarns, and through which chain stitches pile yarns are looped in overlying relation to the laid in weft yarns. Ribbon-like strands of plastic film material are utilized for forming the weft yarns and/or the chain stitch yarns, with all such ribbon-like strands being provided by slitting respective sheets of plastic material concurrently with the knitting operation.

United States Patent 1191 Troy 1 1 May 15, 1973 154] KNIT PILE CARPETFABRIC 3,503,106 3 1970 P611 et al ..28/72 3,626 989 12/1971 Herd1...l39/1l [75] Inventor: James E. Troy, Eden,N.C. 3,645,299 2/1972Eichler 1 139/11 [73] Assigneez Fieldcrest Mills Inc, Eden NC 3 ,110,90511/1963 Rhodes "139/391 X 22 Filed: July 21 1971 FOREIGN PATENTS ORAPPLICATIONS 21 App]. 164 52 1,041,544 5/1953 France ..66/202 PrimaryExaminer-James Kee Chi [52] US. Cl. ..66/191, 66/8656fib616/6l62/52g2,Atmmey Parrot, Be", Seltzen Park & Gibson [51] Int. Cl..H..D04b 9/14,D04b 21/02, DO lb 23/08 57] ABSTRACT [58] Field of Search ..66/190-l95 484 85 78/ CS 72 A warp knit p1le fabnc and method of making the s 5 1i fsame wherein a base fabric is formed from spaced rows of warpwiseextending chain stitches intercon- [56] References Cited nected by laidin weft yarns, and through which chain stitches pile yarns are looped inoverlying relation to UNITED STATES PATENTS the laid in weft yarnsRibbon-like strands of plastic film material are utilized for formingthe weft yarns j i and/or the chain stitch yarns, with all suchribbon-like 3:213:646 10/1965 Van F atten... .:I::::::::: ::::66/l91Strands being Provided by slitting respective Sheets of 2,934,924 5 1960Herrnstadt ..66/191 Plastic material Concurrently with the knitting p2,968,085 1/1961 Matthews 1 66/191 X lion- 2,596,246 5/1952 Johnson etal ..28/1 CS 3,453,816 7/1969 Radoff ..66 202 x 4 Clams, 6 DrawingFigures F 1 K110111100 1,1 1 611111111 filllllilltllmw mittttlllltlnm111111111111 lllllll 11111111111111111111 ("1111111111111119 illllll1311213011014 01: 14M 1 T1NG 1' 1\ @1111111111911 9 slur WI alltlllliilllllilllllln,

11111111111111 P 1 1 1W1] ,1111un1n11111111 11 1\flMll'liilllllllllllllD. f lm mlillllllmm .1 I f1 6% "'7 mm 111531111111. I

SHEET 1 [1F 3 DIRECTION o1 Km mG bHZECTlON OFKN nnNG PATENIEDHAYI 5 I975PATENTEU HAY] 973 SHEET 2 [IF 3 bREcmoM OF KNHTMGV blzecmon OF KN \TT]NG- KNIT PILE CARPET FABRIC The use of warp knit construction is wellknown in the manufacture of pile fabrics such as rugs and carpets, seefor example Clark U. S. Pat. No. 3,140,592. Conventionally, warp knitpile fabrics have heretofore utilized jute yarns for the laid in weftyarns and cotton or rayon for the chain warp yarns. Such fabrics haveoftentimes exhibited a buckling problem, as for example whenwall-to-wall carpet formed thereof is installed, due to varying humidityconditions readily causing elongation, primarily of the laid in juteyarns. This problem is increasingly evident wherein the carpet is laidover a surface, such as concrete, that has not been provided with asuitable moisture barrier surface thereon.

Furthermore, during knitting, the attendant knots present in the juteyarns oftentimes causes the jute yarns to hang up in the guide tubestherefor, thus causing attendant stoppage of the knitting machine. Also,the presence of knots in the jute yarns create points of interferencewith the pile yarns, which also inherently have knots therein, furthercontributing to machine stoppage and/or defective pile fabric.

With the foregoing abbreviated background in mind, it is the primaryobject of this invention to provide a warp knit pile fabric constructionwhich facilitates the knitting thereof and which fabric has built-inproperties to overcome the aforementioned buckling problem.

This is accomplished by using ribbon-like strands of plastic filmmaterial for the laid in weft yarns and/or the warp chain yarns withsuch plastic film material being hydrophobic and being arranged so as toprovide an enhanced moisture resistant backing to the knitted pilefabric. The laid in weft yarns are preferably of such width and are soarranged as to be in somewhat overlapping side by side relationship tomaximize their coverage factor on the backside of the fabric.Contributing to the moisture resistance of the backside of the fabric,in the preferred form of the invention, are the ribbonlike strands ofplastic film material also serving as the chain warp yarns.

For reasons to be pointed out in more detail later, it has beendetermined that the knitting operation is greatly facilitated with amuch lower down time factor when rolls of plastic film material, slitconcurrently with the knitting operation, are utilized as the source forthe laid in weft yarns and chain warp yarns. It has been determined thatone conventional roll of plastic film material about the size of a beamof yarn utilized heretofore, contains a length thereon equivalent to thelength of many beams of conventional yarns. It has also been determinedthat it is a simple matter to splice in a new roll of film material whenthe previous roll is exhausted, merely by utilizing a pressure-sensitivetape to join the trailing and leading ends of the film material. Thus,with the instant invention, a knot-free base fabric can be readily madewhich, as indicated earlier, results in greater efficiency of theknitting machine and, at the same time, a product with enhancedadvantages.

Some of the objects and advantages of the invention having been stated,others will appear as the description proceeds, when taken in connectionwith the accompanying drawings, in which FIG. 1 is an enlarged plan viewofthe pile face of one embodiment of the improved warp knit pile fabricprovided with sinuous weft yarns of ribbon-like strands of plastic filmmaterial interconnecting spaced warpwise rows of chain stitches offibrous yarns with pile yarns looped through the stitches;

FIG. 2 is an inverted plan view looking at the back of the fabric ofFIG. 1, but showing a few additional rows of chain stitches broken awayand omitting the pile yarns and portions of some of the ribbon-likestrands of weft yarn for purposes of clarity;

FIG. 3 is a perspective view of the fabric of FIG. 1 omitting portionsof both the pile yarns and the weft yarns in the right-hand portionthereof, and omitting portions of the pile yarns only in a medialportion thereof;

FIGS. 4 and 5 are views similar to the respective FIGS. 1 and 2 showingasecond embodiment of the im-" proved warp knit fabric in which both thechain stitches and the weft yarns are formed from ribbonlike strands ofplastic film material; and

FIG. 6 is a schematic view ofa warp knitting machine showing anarrangement for slitting sheets of plastic film material, beingwithdrawn from respective rolls thereof, into ribbon-like strandsconcurrently with the knitting operation.

Referring more specifically to the drawings, two embodiments oftheimproved warp knit pile fabric are shown in FIGS. 1, 2 and 3, and inFIGS. 4 and 5, respectively, which may be formed on a conventional warpknitting machine suitably modified to carry out the method of thisinvention, as will be later described. The warp knitting machine isshown schematically, designated at M in FIG. 6, and may be of the typegenerally disclosed in said Clark US Pat. No. 3,140,592, the disclosureof which is incorporated herein by reference.

The first embodiment of the improved warp knit pile fabric shown inFIGS. 1, 2 and 3 comprises a base fabric having a group of warp yarns 10forming weftwise spaced, substantially parallel, warpwise extending rowsof chain stitches 10a. In this particular embodiment, the chain stitchwarp yarns may be of any conventional type, such as rayon or cottonyarns, for example. The base fabric also comprises a group of novel weftyarns l1 laid in the chain stitches with each weft yarn extending in azig-zag or sinuous manner generally warpwise of the fabric andinterconnecting adjacent warpwise rows of the chain stitches 10a. Theweft yarns 11 are especially formed so as to facilitate knitting of thefabric and to provide a moisture resistant backing thereto. To this end,the weft yarns 11 are in the from of ribbonlike strands of hydrophobicplastic film material, and each ribbon-like strand of weft yarn 11 isrelatively thin and is of a width much greater than its thickness. It ispreferred that the ribbon-like strands of weft yarn 11 are each about 2to 3 mils thick and have a width in the range of about to 1 l5 mils. Itis also preferred that the ribbon-like strands forming the weft yarns IIare made from polypropylene or polyester plastic material.

Each weft yarn I1 is laid in and interconnects a plurality of the rowsof chain stitches 10a. Although each ribbon-like strand'of weft yarn 11may extend between only three rows of chain stitches 100, as is the casewith the conventional weft yarns of the conventional warp knit pilefabrics, such as that shown in FIG. 16 of said Clark patent, it ispreferred that each ribbon-like weft yarn interconnects four or moreadjacent rows of chain stitches so as to increase the stability of thepile fabric, especially during processing of the same following theknitting of the pile fabric. Such processing may include steaming,washing and/or dyeing the pile fabric. Also, a suitable backingmaterial, such as high density foam rubber or latex, may each applied tothe back of the pile fabric after knitting the same. It is apparent thatbowing and/or skewing or other distortion of the warp knit pile fabricshould be avoided during such processing, especially during the applyingof any form of back-sizing material to the warp knit pile fabric, sothat the spaced warpwise rows of interconnected chain stitches a will bedisposed in perpendicular relation to the transverse rows of spacedapart chain stitches defined thereby. As best shown in FIG. 2, eachribbonlike strand of weft yarn 11 embraces four rows of chain stitches10a. Although the ribbon-like strands of weft yarn are rolled uponthemselves where they are looped partially around portions of the chainstitches, it is to be noted that each weftwise length or portion is laidin through four weftwise spaced stitches in a substantially flatcondition so that the weftwise flat surfaces of each strand largelyextend in a plane substantially parallel with the plane of the back ofthe base fabric.

Although each ribbon-like strand of weft yarn 11 em braces four adjacentrows of chain stitches 10a, the number of weft yarns 11 is the same asthe number of warpwise rows of chain stitches, with the bights ofadjacent weft yarns being looped around immediately adjacent portions ofinterconnected warpwise extending rows of chain stitches. Consequently,portions of four adjacent weft yarns 11 are disposed in overlappingsubstantially side by side relationship at and between immediatelyweftwise adjacent chain stitches; i.e., major portions of adjacentribbon-like strands extend in side by side partially overlappingrelationship and the ribbon-like strands of weft yarn cover more than 50percent of the area between the spaced rows of chain stitches 10a.

As shown in FIGS. 1 and 3, pile yarns 12 are looped through the rows ofchain stitches 10a, with the lower bights of the pile yarns beingdisposed above and being substantially shielded by the ribbon-likestrands of weft yarn 11. A separate pile yarn 12 is provided for eachwarpwise row of interconnected chain stitches 10a, and each pile yarn 12generally extends in a substantially warpwise direction. However, eachpile yarn zig-zags back and forth between two immediately adjacent rowsof chain stitches 10a so that a row of pile loops 12a is formed from arespective pile yarn 12 between each adjacent pair of warpwise rows ofstitches 10a. Pile yarns 12 are usually relatively large bulky yarns ascompared to the warp yarns 10, and the spacing between adjacent warpwiserows of chain stitches 10a, as well as the size of each stitch in eachwarpwise row are largely determined by the mass or size of the pileyarns 12. It is to be noted in FIG. I, in particular, that two lowerbight portions of adjacent pile yarns 12 are looped through each chainstitch, The height or length of each pile loop 120 is determined by theheight of pile wires or formers (not shown) over which the pile yarns 12are looped during the knitting operation, as disclosed in said Clarkpatent. Although the pile loops 12a are shown in FIG. 3 as being ofsubstantially the same height or length throughout the pile fabric, itis apparent that the loops may be of varying heights and that some orall of the loops may be severed to form cut pile tufts therefrom inselected areas of the pile fabric or throughout the pile fabric, asdesired.

From the foregoing description, it can be seen that, by providing thebase fabric ofthe warp knit pile fabric of the first embodiment withribbon-like strands of hydrophobic plastic film material serving as thesinuous weft yarns ll laid in and interconnecting the warpwise rows ofcontinuous chain stitches 10a, a moisture resistant backing is providedcovering more than 50 percent ofthe area between the'warpwise rowsofchain stitches 10a, thus substantially eliminating the problems ofelongation and consequent buckling of the fabric when installed aswall-to-wall carpet in areas subject to substantial humidity variation.In actual fabrics formed as in FIGS. 1, 2 and 3, it has been determinedthat up to percent of the area between the spaced warpwise rows ofstitches has been covered by weft yarns ll of ribbon-like strands ofhydrophobic plastic film material.

Referring now to FIGS. 4 and 5, a second embodiment of the fabric isshown, which is devised to further facilitate knitting the same and tofurther enhance the moisture resistance of the base fabric. Essentially,the fabric of FIGS. 4 and 5 is quite similar to the fabric of FIGS. 1, 2and 3. Therefore, in order to avoid repetitive description, the elementsof the fabric shown in FIGS. 4 and 5 will bear the same referencecharacters as similar elements of the fabric shown in FIGS. 1, 2 and 3,with the prime notation added. The second embodiment of the improvedwarp knit pile fabric shown in FIGS. 4 and 5 differs from the firstembodiment in that, instead of the warpwise rows of interconnected chainstitches 10a being formed from a conventional type of yarn, as is thecase with respect to the first embodiment the groups of warp yarns 10are each in the form of a ribbon-like strand of hydrophobic plastic filmmaterial of substantially the same type as the ribbon-like strandsforming the sinuous weft yarns 11'. In other words, the entire basefabric may be formed of ribbon-like strands of plastic film materialwith conventional pile yarns 12' being looped through the stitches 10aand to form the raised loops 12a. Although the bight portions of thestitches 10a formed of the ribbon-like strands of warp yarn l0, and'theadjacent portions of the strands which extend through the latter bightportions, are necessarily crowded together or rolled upon themselves, itwill be observed in- FIGS. 4 and 5 that substantial portions of eachstitch between their points of interlacement extend in substantiallyflat condition largely in a plane substantially parallel with the planeof the back of the base fabric. Thus the ribbon-like warp yarn strands10 forming the stitches 10a, and theribbon-like weft yarns 11', cover atleast about percent of the back of the base fabric to provide anenhanced moisture resistance thereto. In a typical fabric formed as inFIGS. 4 and 5, it has been determined that up to percent of the entirearea of the back of the warp knit pile fabric has been covered by theribbon-like strands of plastic material forming both the warp yarns l0"and the weft yarns 11.

Another advantage in providing weft yarns formed of ribbon-like strandsof hydrophobic plastic film material in the base fabric of the warp knitpile fabric, which advantage is further enhanced by also providing chainstitch warp yarns 10 formed of ribbon-like strands of hydrophobicplastic material, is that the ribbon-like strands of hydrophobic plasticmaterial shield the major portions of the lower bights of the pile yarns12 or 12, as the case may be, to substantially prevent any back sizingmaterials, such as latex or high density foam rubber, from penetratingthrough to the upper surfaces of the lower bights of the pile yarnsduring application of the back sizing material to the warp knit pilefabric as is desirable.

According to the method of this invention, the weft yarns 11 of thefirst embodiment of the fabric (FIGS. 1-3), and both the weft yarns l1and the chain stitch warp yarns of the second embodiment of the fabric(FIGS. 4 and 5), are formed concurrently with the knitting of the fabricin each instance, thereby obviating the need for preparing and windingyarns onto bobbins, spools or beams before they can be fed to theknitting machine, and also obviating the necessity for piecing up thetrailing ends of the corresponding yarns to the leading ends of yarnsfrom a new beam or from individual yarn sources, as the case may be,whenever the supply therefor is exhausted as has been customaryheretofore.

A suitable arrangement of equipment for carrying out the method of thisinvention is shown schematically in FIG. 6, such equipment beingarranged, in this instance, for knitting the second embodiment of thefabric shown in FIGS. 4 and 5. As shown in FIG. 6, pile yarns 12' aredrawn from a suitable source shown in the form of a beam 12b, and thepile yarns then may pass upwardly and in a substantially horizontal paththrough a suitable pile yarn tension means 12c. From tension means 12c,pile yarns 12' pass downwardly to the warp knitting machine M where theypass through the usual pile yarn guides associated with the knittinginstrumentalities M, not shown in the present drawings but being fullydisclosed in said Clark US. Pat. No. 3,140,592.

In order to form the ribbon-like strands of plastic material serving asthe chain stitch warp yarns 10 and the sinuous weft yarns llconcurrently with the knitting operation, sheets of plastic filmmaterial 10b, 11b are withdrawn from respective rolls 10c, 11c and thenpass through respective film slitting means 14, 15 which slit therespective sheets of plastic film material 10b, 11b into a plurality ofparallel ribbon-like strands forming the respective warp yarns and weftyarns 10', 11'. The warp and weft yarns 10', 11 pass directly from therespective film slitting means l4, 15 to the warp knitting machine Mwhile the warp knitting machine is in operation and is forming the warpknit pile fabric generally designated at F in FIG. 6. The fabric F maybe taken up by any suitable take-up means 16. The width of the sheets10b, 11b is about the same as the width of the fabric F being knit, andsuitable means, not shown, may be provided for applying the desiredamount of tension to the sheets 10b, 11b.

Each slitting means l4, 15 may include any suitable means for slittingthe corresponding sheet of plastic film material into the desired widthsof ribbon-likestrands, such as a plurality of thin parallel circularcutters or stationary blades spaced the desired distance apart from eachother. Since film slitting means are well known, a detailed illustrationand description of the film slitting means l4, 15 is deemed unnecessary.

In forming the warp knit pile fabric of FIGS. 1, 2 and 3, it is apparentthat the method may be carried out utilizing apparatus such as thatdescribed with respect to FIG. 6 with the exception that a source ofconventional yarns would be used in place of the sheet of plastic filmmaterial 10b, the roll 10c, the film slitting means 14 and theribbon-like strands 10' of plastic film material.

It is thus seen that there is provided a method of making a warp knitpile fabric in which a base fabric is knit from a group of warp yarnsand a group of weft yarns by forming spaced warpwise extending rows ofinterconnected chain stitches from the warp yarns while laying in theweft yarns to interconnect the rows of chain stitches, during which pileyarns are looped through the chain stitches above the laid in weft yarnswith the pile yarns extending upwardly from the base fabric, and whereinat least one sheet of plastic film material, being withdrawn from a rollthereof, is slit into ribbon-like film strands concurrently with theknitting operation, while utilizing the ribbon-like film strands beingformed as the source of supply for at least one of the groups of yarnsforming the base fabric; i.e., the ribbon-like film strands being formedserve as the source of supply for either the weft yarns or the warpyarns or both the weft yarns and the warp yarns.

It is apparent that the method greatly facilitates the knitting of thepile fabric by eliminating the need for preparing and feedingconventional yarns to the warp knitting machine as the source of supplyfor the weft yarns and/or the warp yarns. Also, when a roll of theplastic film material is exhausted, it is a simple matter to replace thesame with a new roll and to splice the leading end of the new roll tothe trailing end of the sheet of plastic film material then approachingthe corresponding film splitting means 14 or 15 by means of a strip ofpressure-sensitve tape. In the event of individual strands 10' or 11becoming parted unintentionally, they also may be spliced by utilizingpressure sensitive tape to join the trailing and leading ends of theribbonlike strands, thus avoiding knots in the base fabric and resultingin greater efficiency of the warp knitting machine M.

In the drawings and specification, there have been set forth preferredembodiments of the invention and, although specific terms are employed,they are used in a generic and descriptive sense only and not forpurposes of limitation.

That which is claimed is:

l. A warp knit pile fabric comprising a base fabric having a group ofwarp yarns forming spaced rows of warpwise extending chain stitches anda group of weft yarns laid in the chain stitches with each weft yarnextending in a zig-zag manner and interconnecting adjacent rows of thechain stitches, and pile yarns looped through the chain stitches abovesaid laid in weft yarns and extending upwardly from said base fabric;characterized' in that at least said group of weft yarns is formed ofribbon-like strands of plastic film material each about 2 to 3 milsthick and of a width within the range of about to l 15 mils with each ofsaid ribbonlike strands interconnecting at least four adjacent rows ofsaid chain stitches and with the strands being positioned with majorportions of adjacent strands in side 3. A warp knit pile fabricaccording to claim 1- wherein said ribbon-like strands are ofpolypropylene plastic material.

4. A warp knit pile fabric according to claim 1 wherein said ribbon-likestrands are of polyester plastic

1. A warp knit pile fabric comprising a base fabric having a group ofwarp yarns forming spaced rows of warpwise extending chain stitches anda group of weft yarns laid in the chain stitches with each weft yarnextending in a zig-zag manner and interconnecting adjacent rows of thechain stitches, and pile yarns looped through the chain stitches abovesaid laid in weft yarns and extending upwardly from said base fabric;characterized in that at least said group of weft yarns is formed ofribbonlike strands of plastic film material each about 2 to 3 mils thickand of a width within the range of about 80 to 115 mils with each ofsaid ribbon-like strands interconnecting at least four adjacent rows ofsaid chain stitches and with the strands being positioned with majorportions of adjacent strands in side by side partially overlappingrelationship and covering more than 50 percent of the area between thespaced rows of chain stitches.
 2. A warp knit pile fabric according toclaim 1 wherein said group of warp yarns also are in the form ofribbon-like strands of plastic film material.
 3. A warp knit pile fabricaccording to claim 1 wherein said ribbon-like strands are ofpolypropylene plastic material.
 4. A warp knit pile fabric according toclaim 1 wherein said ribbon-like strands are of polyester plasticmaterial.